A case of metastatic renal cell carcinoma to the ovary.

A 52-year-old woman had a pathological fracture of the right femur. On histopathological examination bone metastasis from renal cell carcinoma was suspected. Abdominal computed tomography showed a heterogeneous mass (9.1 x 7.8 x 6.5 cm) in the left kidney and a cystic multilocular mass (12 x 10 cm) in the pelvis. Bone scintigraphy revealed an abnormal uptake in the left coracoid process, right third rib, and right distal femur and proximal tibia. Clinical diagnosis was left renal cancer with multiple bone metastases (cT2NOM1, stage IV) and a right ovarian tumor. We performed left radical nephrectomy and resection of right ovarian tumor by bilateral adnexectomy. On histopathological examination, the left kidney tumor was diagnosed as renal cell carcinoma (clear cell carcinoma with chromophobe component, G2 > G1). The ovarian tumor consisted of carcinoma of clear cell type (G2) that resembled components of left renal cell carcinoma, confirming the diagnosis of metastatic renal clear cell carcinoma to the ovary. Although she underwent immunotherapy with interferon, she died 10 months after nephrectomy. Metastasis to the ovary from renal clear cell carcinoma is very rare and only 18 cases have been reported in the literature. This rarity may be related to the difficulty of differential diagnosis between metastatic renal cell carcinoma to the ovary and primary ovarian clear cell carcinoma. Elaborate analysis of microscopic features and immunohistochemical profiles may help in the distinction of this metastatic lesion.